I'm not sure "most", as in, the number of linux games, is relevant, since there are very few high-profile games on linux. I think those matter most. UT3, ET: QW could use a boost in performance on systems with low-to-midrange discrete cards.

ok, with those cards it's probably important too...

@UT3: last time I checked, the linux client was not released yet and there are very few other "high-profile games" on linux